Windshield visors have been attached to trucks and other motor vehicles to provide protection against sun and rain and to provide increased visibility. They generally extend beyond the forward edge of the roof and over the front windshield of the motor vehicle.
A concern with windshield visors is that sufficient structural mounting and air relief are provided. The forward movement of the vehicle causes air flowing upward and across the front windshield to provide a force against the bottom surface of the visor. During high speed travel, the force of the air has been found to rip poorly designed visors from the motor vehicle. Even if the visor is securely attached, the differences in air pressure across the lower surface can cause "flutter." This is exhibited by a bending and/or twisting motion. Flutter can also result if the visor is not sufficiently rigid and strong. The occurrence of flutter is not only distracting to the vehicle occupants, but it can also fatigue the visor at those locations where it is mounted to the vehicle and eventually cause it to rip off the vehicle's roof. Therefore, windshield visors should be designed so they can securely attach to the vehicle, and provide sufficient air relief and rigidity.
Roof mounted windshield visors are fairly common and are described, for example, in U.S. Pat. Nos. Des. 288,309 to Lund; Des. 312,238 to Lund; 4,966,404 to Lund; Des. 301,450 to Kingsly; Des. 301,028 to Buck;. 291,295 to Lund; Des. 288,310 to Lund; U.S. Pat. No. 4,726,619 to Haugestad; and U.S. Pat. No. 4,842,320 to Kingsley. The windshield visors described by these patents can be characterized as roof mounted visors since they require fastening to the motor vehicle's roof at several locations. Most commonly, the fastening points are in the roof immediately above the front windshield. The visor then extends from the forward edge of the roof and outward, over the windshield.
Other windshield visors which may not be technically considered "roof mounted" are described by U.S. Pat. No. 4,758,040 to Kingsley et al. and Des. 252,680 to Kingsley et al. These visors are mounted at the juncture of the roof and the edge of the windshield. Similar to the roof mounted windshield visors, however, they require fastening at several points by putting holes at locations which are highly visible if the visor is ever removed.
Many of the above-described visors provide sufficient structural support. Their points of attachment, however, are in the roof of the vehicle or at the juncture of the roof and the edge of the windshield. Owners of new trucks or utility vehicles are often reluctant to put holes in their new vehicle at those highly visible locations. If they ever decide to remove the windshield visor, expensive repair work would be necessary to remove the scars and return the vehicle to its original appearance. Furthermore, the repairs may never completely hide the fact that holes were drilled or punched in the roof. Similarly, people who lease motor vehicles are often reluctant to purchase a windshield visor since the visor may have to remain with the motor vehicle after the lease expires.
A new style of light truck and utility vehicle has been developed which is more aerodynamic than older trucks. This new style is characterized by a more rounded and sleeker look, and the replacement of exterior drip rails or rain gutters with "aircraft style doors" which provide internal rain gutters. For many consumers, the presently available windshield visors do not provide a satisfactory look on these newly designed vehicles. A part of the problem appears to be that several roof mounted visors do not adequately fit the curved contour of the roof. In addition, a sleeker or softer looking visor is desired for these vehicles.